Probing the topological exciton condensate via Coulomb drag

TL;DR

This paper predicts the critical temperature for exciton condensation in topological insulator thin films and proposes Coulomb drag resistivity measurements as a way to detect this transition.

Contribution

It provides a calculation of the critical temperature considering screening effects and suggests Coulomb drag as an experimental probe for the exciton condensate transition.

Findings

Critical temperature for exciton condensation calculated.

Coulomb drag resistivity shows an upturn near the transition.

Proposes Coulomb drag measurement as a probe for the exciton condensate.

Abstract

The onset of exciton condensation in a topological insulator thin film was recently predicted. We calculate the critical temperature for this transition, taking into account screening effects. Furthermore, we show that the proximity to this transition can be probed by measuring the Coulomb drag resistivity between the surfaces of the thin film as a function of temperature. This resistivity shows an upturn upon approaching the exciton-condensed state.